Control logic for gas discharge display panel

ABSTRACT

An external source supplies command and data bytes which are decoded to control the energization of a gas discharge display panel in order to display thereon alpha-numeric characters and other symbols. Each command is decoded to determine whether it is a POSITION command or one of the following commands: WRITE CHARACTER, WRITE SLICE, ERASE DATA and ERASE PANEL. If a POSITION command is decoded, following data bytes are decoded and stored as the starting cell address of the gas panel. If the next command is a WRITE CHARACTER or WRITE SLICE command, the following data byte specifies the code of a character or the horizontal data slice, respectively, to be written or displayed in the panel beginning at the starting cell address. Corresponding individual row and column latchable drivers or bistable switching circuits are then set to select the panel drive lines which are to be energized to illuminate the gas cells designated by the character or slice data byte. If the next command had been an ERASE DATA command, the following data byte would have specified the width and height of a block of cells to be erased, and the corresponding panel line drivers would have been set to permit extinguishment or erasure of the cells in the specified block. An ERASE PANEL command causes all the cells of the panel to be simultaneously erased. At an appropriate time after the selected drivers are latched, an analog power circuit causes the set drivers to apply appropriate sustain, write or erase voltages to the selected panel lines.

United States Patent Mauro, Jr.

[ Sept. 2, 1975 CONTROL LOGIC FOR GAS DISCHARGE DISPLAY PANEL Nickolas Ralph Mauro, Jr., Woodstock, NY.

[75] Inventor:

['73] Assignee: International Business Machines Corporation, Armonk, NY.

22 Filed: June 26,1973

21 Appl.No.:373,700

Primary E.raminerDavid L. Trafton Attorney, Agent, or FirmSughrue, Rothwell, Mion,

Zinn and Macpeak [5 7] ABSTRACT An external source supplies command and data bytes which are decoded to control the energization of a gas I I I PROCESSOR CONTROL CHIP -DECODEO DRIVER SELECT SI discharge display panel in order to display thereon alpha-numeric characters and other symbols. Each command is decoded to determine whether it is a POSI- TION command or one of the following commands: WRITE Cl-IAILACFER, WRITE SLICE, ERASE DATA and ERASE PANEL. If a POSITION command is decoded, following data bytes are decoded and stored as the starting cell address of the gas panel. If the next command is a WRITE CHARACTER or WRITE SLICE command, the following data I byte specifies the code of a character or the horizontal data slice, respectively, to be written or displayed in the panel beginning at the starting cell address. Corresponding individual row and column latchable drivers or bistable switching circuits are then set to select the panel drive lines which are to be energized to illuminate the gas cells designated by the character or slice data byte. If the next command had been an ERASE DATA command, the following data byte would have specified the width and height of a block of cells to be erased, and the corresponding panel line drivers would have been set to permit extinguishment or erasure of the cells in the specified block. An ERASE PANEL command causes all the cells of the panel to be simultaneously erased. At an appropriate time after the selected drivers are latched, an analog power circuit causes the set drivers to apply appropriate sustain, write or erase voltages to the selected panel lines.

10 Claims, 25 Drawing Figures ESB LA.Y IMEL "J ISECM TED CEIHISL VERTICAL I ISOLATION CIRCUITS VERTICAL LINE DRIVERS HORIZONTAL ISOLATION CIRCUITS ANALOG POWER CIRCUITS I I I I I I I I I l I I I I I LBR PATENTEUSEP 2M5 SW 6 3,903,516

FIG. 5A RESET, we a COMMAND DECODE IN ITIALIZE LEVEL "5 500 MS INPUT I NITIALIZE LVL= ACTLVE INPUT 08C. PULSE BLOCKED YES 'BLOCK SET INPUTOSC. FREQDVDRS. HDVDR PULSE F1 AND F2 STEP PULSE 'CLR SUSTAIN W UNA CLR YES J 1 CYCLE STEP PULSE POSITION LTH W SET HZ coARsE CHAR CODE CMD LTH LTH COMPLEMENT C R C F1 DVDR L LR HZ FINE V EXECUTE CMD LTH LTH 'CLR QCLR ALL VT COARSE V SEQUENCE 'COMPLEMENT CMD LTH LTHS F2 DVDR 'CLR 'CLR VT FINE cuc-4 CMD LTH N 'CLR 'CLR WRT CHAR cues GEN CMD LTH TO 0 NA EARLY 'CLR 'CLR WRTSLICE PULSE CMD LTH LTH 'sEE ERAsEUAEA POSITION REGS CMD LTH TO (A 'QJGEAN SET OCLR ERAsE. PANEL POSITION LD CMD LTH LEN OCLR OCLR RECYCLE ACCEPT LTH LTH PATENTEU 35? 21975 SHEET 22:28 20522 4b QE z omw w omw @5056 m3. H 303. -30 5Q -30 Eu P 25 5528 05% w 25 26 mm 8 SHEET E8 is H 501; P 5

$4 255 mom PATENTEDSEP 2191s 

1. Control logic for controlling the display of a pattern in a gas discharge display panel including: a matrix of mxn gas discharge cells defined by the intersections of m row panel conductors and n column panel conductors; a selectable driver circuit connected to each panel conductor and selectable in response to low voltage control signals; and high voltage circuit means for applying, in response to low voltage control signals, high voltage sustain, write or erase operating signals through selected drivers to their connected panel conductors to affect the condition of each gas cell whose associated row and column driver is selected, whereby one or more illuminated gas cells forming a displayed pattern may be sustained in a state of illumination or extinguished or whereby one or more gas cells may be illuminated to form a display pattern; said control logic comprising: a. command decoder means for decoding digital command signals specifying a command to be executed; b. position data storage means for storing data associated with a decoded position command signal and identifying a pair of row and column driver circuits connected to a corresponding pair of row and column panel conductors whose intersection defines the address of a starting gas cell; c. pattern data storage means for storing pattern data associated with a decoded panel operation command signal and identifying a pattern of cells whose conditions are to be affected in accordance with the stored data pattern; d. counter means responsive to the stored position data, to the stored pattern data and to the decoded panel operation command signal for producing first low voltage control signals for sequentially selecting a plurality of pairs of row and column driver circuits, beginning with said pair of driver circuits associated with said starting cell; and e. logic control means responsive to the decoded panel operation command signal for producing second low voltage control signals and applying them to the high voltage circuit means, so that appropriate high voltage operating signals are applied through said selected pair of driver circuits to affect the condition of the gas cells identified by the pairs of row and vertical panel conductors connected to said selected pairs of driver circuits.
 2. Control logic as defined in claim 1 wherein said panel operation command is a write-pattern command, and wherein said logic control means comprises means responsive to the decoder write-pattern command for producing a low voltage write control signal in response to which the high voltage circuit means applies write operating voltages to said pairs of row And column panel conductors connected to said selected pairs of driver circuits, whereby the identified gas cells are illuminated in accordance with the stored pattern data.
 3. Control logic as defined in claim 1 wherein said panel operation command is a write-pattern command, and wherein said logic control means comprises means responsive to a decoded write-pattern command and to a series of row pattern data for sequentially transferring the series of row pattern data to said pattern data storage means; said counter means being responsive to the sequentially stored rows of pattern data for sequentially selecting corresponding row driver circuits and corresponding column driver circuits within each selected row of driver circuits, whereby the identified gas cells are illuminated in accordance with the sequentially stored series of row pattern data.
 4. Control logic as defined in claim 1 wherein said panel operation command is a write-character command, and further comprising read-only storage means for storing a plurality of unique characters each consisting of rows of pattern data; said logic control means comprising means responsive to a decoded write-character command and to a unique character data for sequentially transferring the rows of pattern data corresponding to said unique character data to said pattern data storage means; said counter means being responsive to the sequentially stored rows of pattern data for sequentially selecting corresponding row driver circuits and corresponding column driver circuits within each selected row of driver circuits, whereby the gas cells identified by the sequentially stored rows of pattern data are illuminated to display the unique character.
 5. Control logic as defined in claim 1 wherein said panel operation command is an erase-data block command, and wherein the stored pattern data identifies the number of row panel conductors and the number of column panel conductors whose intersections identify a block of gas cells to be extinguished, beginning with said starting gas cell; said counter means being responsive to the decoded erase-data block command for sequentially selecting row and column driver circuits identified by the stored data pattern and said starting gas cell; said logic control means comprising means responsive to the decoded erase-data block signal for producing a second low voltage erase-data block signal in response to which the high voltage circuit means applies high voltage operating signals to all selected drive circuits so that said block of cells is extinguished.
 6. Control logic for controlling the display of a pattern in a gas discharge display panel including: a matrix of m X n gass discharge cells defined by the intersections of m row panel conductors and n column panel conductors; a selectable driver circuit connected to each panel conductor and selectable in response to low voltage control signals; and high voltage circuit means for applying, in response to low voltage control signals, high voltage sustain, write or erase operating signals through selected drivers to their connected panel conductors to affect the condition of each gas cell whose associated row and column driver is selected, whereby one or more illuminated gas cells forming a displayed pattern may be sustained in a state of illumination or extinguished or whereby one or more gas cells may be illuminated to form a displayed pattern; said control logic comprising: a. command decoder means for decoding an erase panel command; and b. logic control means responsive to the decoded erase panel command for producing a plurality of alternate shortened, low voltage vertical and horizontal sustain control signals interleaved between shortened low voltage restore control signals, said shortened sustain and restore control signals controlling said high voltage circuit means to provide to said panel conductors erase operating signals in the form of a plurality of shortened high voltage sustain operating siGnals to cause all illuminated panel gas cells to be extinguished.
 7. Control logic as defined in claim 2 wherein said counter means comprises: position counter means responsive to the contents of said position data storage means defining the address of a starting gas cell, said position counter means incrementing said contents of said position data storage means for sequentially selecting a row driver circuit and a plurality of column driver circuits in response to said stored pattern data beginning with the driver circuits associated with said starting cell.
 8. Control logic as defined in claim 7 wherein said counter means further comprises multipurpose counter means responsive to said command decoder means for controlling the number of increments taken by said position counter means.
 9. Control logic as defined in claim 4 wherein said counter means comprises: position counter means responsive to the row position contents of said position data storage means for selecting a row driver circuit, said position counter means incrementing said row position contents of said position data storage means to allow the sequential selection of said corresponding row driver circuits; and multipurpose counter means for controlling said read only storage means for transferring a row of pattern data corresponding to said unique character data for each selected row driver to said pattern data storage means, said position counter means being responsive to said stored row of pattern data and controlled by said multipurpose counter means for sequentially selecting said corresponding column driver circuits.
 10. Control logic as defined in claim 5 wherein said counter means comprises: position counter means responsive to the contents of said position data storage means defining the address of a starting gas cell; and multipurpose counter means responsive to said number of column panel conductors of said stored pattern data for controlling said position counter means to sequentially select said column driver circuits identified by said stored pattern data and responsive to said number of row panel conductors of said stored pattern data for controlling said position counter means to sequentially select said row driver circuits identified by said stored pattern data, thereby identifying said block of gas cells to be extinguished. 